COPPER, STEEL, AND BANK-NOTE ENGRAVING. 601 



stood tlie importance of engraving as a means of increasing his 

 fame and wealth, and directed Vorsterman and others, as Raphael 

 had directed Marc Antonio. Rubens's theory of engraving was 

 that it ought not to give accurately the local color of the jjicture, 

 which would appear wanting in harmony when not associated 

 with the hues of the painting ; and it was one of his anxieties so 

 to direct his engravers that the result might be a fine plate inde- 

 pendent of what he had painted. To this end he also helped his 

 engravers by drawings, and he sometimes went so far as to indi- 

 cate what he thought the best direction for the lines. 



Previous to the year 1830 only copper plate was used by en- 

 gravers, because up to that time it was not thought possible to 

 make steel soft enough to cut easily and smoothly. The first 

 plate produced that could be used was called "silver steel." 

 Later there was manufactured the " Prussian steel " plate, which 

 was a slight improvement in fineness of grain. Other and greater 

 improvements followed, until now steel has almost entirely super- 

 seded copper. 



Decarbonated cast steel is used for general engraving purposes 

 and must be of very fine grain, and very soft as compared with 

 natural cast steel. The plates are rolled out from bars of steel in 

 its natural state, then decarbonated and cut to about the size de- 

 sired, leaving enough margin to square the edges, which are fin- 

 ished with a wide bevel. After the plate has been cut to size, it 

 is flattened by laying it upon a copper anvil and hammering with 

 a wooden mallet until it is as flat as is possible to get it by that 

 process. A uniform thickness and perfectly flat surface are then 

 given to the plate by grinding sometimes by hand, usually by 

 machine the latter process being the better, as it is the more 

 perfect in its results. By grading the stones used in this grind- 

 ing from coarse to fine, the plate is left ready for the final finish, 

 which is given by burnishing and rubbing with very fine emery 

 leather made for the purpose, from the finest grade of emery that 

 can be had. 



Copper plate is still used to a considerable extent for visiting 

 cards, invitations, and such small work as calls for only a limited 

 number of impressions, for copper will not stand nearly as much 

 wear as steel, often wearing out in one thousand impressions, 

 while ten or even fifteen thousand can be taken from steel, and, 

 if the plate is hardened, as is often done, one hundred thousand 

 have sometimes been pulled before the plate has entirely given 

 out. Copper is also used in some cases for the cheaper classes of 

 picture work, such as book illustrations, but it is usually coated 

 with steel or nickel by precipitation, this facing taking the wear 

 instead of the copper. 



The tools used in steel engraving are about the same as those 



VOL. XLVI. 44 



